Doctor Who: Fight the Future
by Otherwolf
Summary: Set between The Day of the Doctor and The Time of the Doctor. After a slight accident (which was most certainly not due to the Doctor failing to pay attention), a mysterious stranger appears onboard the TARDIS. The Doctor and Clara are surprised - but not as much as they are when they realise who the stranger is.
1. Arrival

1

Arrival

"Run!"

The sound of something being whacked repeatedly disrupted the calm inside the TARDIS as it drifted through empty space.

"Come on, run, you stupid thing!"

The Eleventh Doctor's boyish face popped out from behind the TARDIS console. "What on earth are you doing?"

"It's my stupid computer," said Clara. She was sitting on the steps leading up to the central platform, balancing her laptop on her knees. She gave it another whack. "It's so slow. It's taking forever to start up."

The Doctor straightened his bowtie and grinned. "Well, if you need a computer repair man, you know who to ask!"

"Yeah," said Clara. "The girl who had her mind hacked and updated with computer whiz-kid skills."

The Doctor looked miffed. He came round to her side of the console. "Fine. Why do you want to fix it, anyway? The TARDIS is far better than any silly human invention!" He patted the console. "Right, old girl?"

The TARDIS _clong_ed, the sound reverberating in the pale blue glow of the console room.

"Oh, young girl, then," said the Doctor. "The point being, you don't need a computer when you've got me!"

"I need to access my email," said Clara. "And you can't do that, can you?"

"Of course not," the Doctor said, a little too quickly. "Ha! The very idea!"

Clara narrowed her eyes at him.

"Can't you use your phone?" said the Doctor, in an effort to change topic.

"Battery's died." Clara was still giving the Doctor a Look. She was good at them.

The Doctor looked away sheepishly. "Well," he mumbled, "I offered my help. I'll leave you to it."

As he turned to move back around the console, Clara said. "Wait. You _can_ do something, can't you? Do a thing?"

"What thing?"

"You know, a thing! A sonic thing! Sonic it and make the computer run faster!"

The Doctor affected an air of superiority. "The sonic screwdriver is not a toy. It can't just do anything you care to name."

"No, indeed," said Clara. "Especially wood."

"Oi!" said the Doctor. "None of that! Anyway, I couldn't possibly help. Augmenting your laptop with my screwdriver would be a gross misuse of Time Lord technology."

Clara grinned. "In other words, you can't fix it, and don't want to admit it."

"As a matter of fact, I could hook your laptop up to the TARDIS and turn it into the most powerful computer in the world. Not that I'm going to. But I could."

Clara wasn't fooled for a second. She knew that the Doctor couldn't resist a chance to show off. "Never mind," she said, offhandedly. "You probably can't do anything anyway. You're just pretending you can to look clever."

"I am clever!" The Doctor came over and snatched up her laptop. "Just watch," he said with a grin. "You'll be the envy of all your mates at school."

"I'm a teacher, not a school kid," she reminded him.

"Can't imagine why. It's much more fun being a kid." The Doctor placed the laptop on the TARDIS console. "Right, now I just need to interface it."

"I have the cable thingy in my bag," said Clara.

The Doctor shook his head and chuckled. "The TARDIS doesn't need such primitive things as _cables_. Just placing the computer near it will work. Right!" He began fiddling with switches on the console. "Just need to connect to the device… done! Now I need to reroute power from somewhere. Hmmm…" He examined the TARDIS' own computer screen. "Need to find something we're not using… oxygen? No, we probably need that. Karaoke machine? No, we _definitely_ need that. Aha!" His face lit up. "The BBC!"

"BBC?" said Clara. "What's that?"

"No idea!" the Doctor said cheerfully. "And since I don't know what it is, it mustn't be important!" He pressed a button.

The TARDIS _clong_ed again.

"Steady on, old, uh, young girl," said the Doctor, giving the console a reassuring pat. "Just shifting some power."

"Um," said Clara. "Are you sure you know what you're doing?"

"Of course!" The Doctor continued pressing buttons.

The TARDIS _clong_ed for a third time, sounding louder.

"Doctor, I'm really not sure that whatever you did was a good idea," said Clara.

"It's fine!" said the Doctor, waving his arms dismissively. "Look, I'll prove it. I'll find out what the BBC does." He began rapidly pressing buttons on the screen. "BBC… aha! Found it! It's the Big- oh."

"Oh?" said Clara. "Oh what?"

"Oh _dear_," said the Doctor. He suddenly noticed that, on another part of the console, a red light was flashing. He looked at Clara. His face wore the manic grin of someone who knows they're in deep trouble and are desperately trying to pretend otherwise. "Word of advice. You might want to hold on."

"To what?!"

"Anything!" The Doctor suddenly grabbed the console and held on to it tightly. Alarmed, Clara followed suit.

"Doctor," she said, "what _is_ the BBC?"

"Well, as a matter of fact," he said, trying and failing to sound casual, "it turns out that it's actually very important. It prevents the TARDIS from crashing into-"

He was cut off by an especially loud _clong_ from the TARDIS. "Well," he said, "this is probably not going to be good."

Suddenly, everything went crazy.

The entire room began shaking violently. Clara gripped the console as hard as she could to stop herself falling over. The Doctor did likewise, but slipped and was thrown to the floor. The TARDIS' cloister bell was ringing loudly. The engines made their familiar screeching sound. There was a big bang, and then a deep noise that sounded like something ripping.

And then, just as suddenly, silence.

Cautiously, Clara looked around. Everything was still again. The room was exactly as it had been before… with one slight difference.

"Ah!" said the Doctor. He quickly leapt to his feet and began fiddling with the console. "That could have been very bad. I think we got away with it. Bit of a lucky escape, really."

"Doctor," said Clara.

"We're no longer in flight," said the Doctor, not paying attention. "Let's see… yep! We had a mid-air collision. Well, mid-space collision. Knocked us right off track. We've landed. On Earth, for some reason." He examined the screen. "Britain… near London. Why is it always London? It's near the present. Your present, I mean. Possibly a year or two in the future for you."

"Doctor," Clara said again.

"Wonder where the other one ended up," the Doctor continued, evidently speaking to himself. "It must have hit us, bounced off, and returned to its own time. Because we weren't on any particular fixed course, we seem to have been dragged along with it." He examined the screen in front of him. "No local activity, so it's not around at the moment. We probably missed by a few days either side. Still," he straightened up and adjusted his bowtie, "we definitely shouldn't stick around. Otherwise we could be in big trouble."

"_Doctor_!" Clara sounded much more urgent.

A frown crossed the Doctor's face. "Hang on," he said. "Here's me being all clever and intentionally mysterious, and you're not being impressed and asking questions. Why not?"

Clara pointed. The Doctor turned to look.

There was another person in the TARDIS.

Someone was standing close to the back wall, partially hidden. Someone who definitely hadn't been there a moment ago.

"Hello," said the man, and fell over.

Neither Clara nor the Doctor moved. They stared at him, and then at each other. Then back to the man, who was sprawled on the floor.

Whoever he was, he looked like a normal, average man in his early thirties. His skin was very pale and his hair was a deep, rusty red colour. He looked rather thin. Intriguingly, he was wearing a dark purple jacket that was too big for him, dark trousers, a waistcoat, and, most notably, a bowtie.

"Doctor," said Clara, "what's going on? Who is that?"

"Oh, not good, so very not good," said the Doctor, flapping his arms around in a panic. "This can't happen. This _shouldn't_ happen. Why has this happened?"

Clara grabbed one of the flailing arms. "Stop that!" she said. "Listen to me. Explain what's going on, because I am very confused right now."

The Doctor took a few deep breaths. "Okay," he said. "I'll explain quickly, before… _he_ wakes up." He cast a worried eye over the figure sprawled on the floor, apparently unconscious. "You see, the BBC is the Big Barrier Control."

"Big Barrier? Seriously?" said Clara. "As opposed to what, the small barrier?

"No!" the Doctor was becoming more agitated. "The TARDIS has lots of protective measures surrounding and within it. I call that one the Big Barrier because it's probably the most important of all of them."

"Why? What does it do?" Clara demanded.

"It stops the TARDIS from colliding with, well…"

"With…?"

"Think about it!" said the Doctor. "I zip about all over the place, backwards and forwards in time, here, there, everywhere! There's a danger the TARDIS could collide with the one thing it absolutely must not ever bump into!"

"Which is what?"

"What d'you think? _Itself__!_"

The figure groaned, and began stirring.

"What do you mean?" said Clara, a note of panic in her voice.

"I mean," said the Doctor, watching the figure with apprehension, "that the TARDIS has just encountered itself from the future. It must be the future – if it was the past then logically I'd remember this. Which I don't." The Doctor took a deep breath. "Present and future collided for a moment. And they left something from behind."

Clara looked at the mysterious man again. "Him?"

"Yes. He's from the future. _My_ future." The Doctor looked at the TARDIS console screen again. "According to the readings, not too far in my future."

"But who is he?"

"Well-"

The Doctor was cut off by a louder groan. Suddenly, the man's eyes snapped open. He looked at them. In one move, he sprang to his feet.

"There we go!" the man said happily. "Brrr! Oh, that tingled. That was fun!" He smiled, and then clutched one of the railings beside the steps. He made a choking sound, and then coughed a cloud of golden energy from his mouth.

"I knew it," said the Doctor grimly.

"What?" Clara looked very confused.

"That's regeneration energy. He's a Time Lord. One that's just regenerated."

"But," Clara looked at the man and back to the Doctor, "I thought all the Time Lords were locked in another dimension!"

"They are. So either this one escaped, or he's…"

The stranger had regained his balance. "Ah! That's better. Now, give me a moment." He began running his hands over his body. "All this new stuff. Let's see… still male… no facial hair; well, easy to maintain I suppose… ooh, but I've got lots of hair everywhere else… think I've lost a bit of weight too. And I seem to be a bit taller. Great!" He smiled at them. "Now then, Doctor! Clara! Good to see you! It worked, then!"

The two of them stared at him wordlessly.

"Oh!" he babbled on. "You're probably wondering who I am. Behold! My ID!" He whipped something out of his jacket pocket.

It was a sonic screwdriver.

The Doctor looked at it. Slowly, he reached into his own jacket – a jacket, now they could see them both clearly, that was identical to the one the stranger was wearing – and extracted his own screwdriver. He cautiously stepped forward and touched the tip of his own screwdriver to the other man's.

There was a crackling noise, and sparks erupted from the point they were touching.

The Doctor withdrew his screwdriver. He smiled grimly again. "As I thought," he said.

"What was that?" Clara was hopelessly lost at this point. She was aware that some meaningful exchange of information was going on. However, it was one that she couldn't understand.

The Doctor turned to her. "They're the same. The same screwdriver, I mean. Touching them together caused a mini paradox, hence the sparking. He turned back to the other man. "The same screwdriver, from a different time. At a guess, I'd say the not-too-distant future?"

The man nodded.

The Doctor turned back to Clara with a meaningful look on his face. Evidently he felt that she would now understand the situation.

She did not.

"But who is he?!" she insisted.

The Doctor waved his arms. "Think about it! My TARDIS, from the future! My screwdriver, from the future! He's just regenerated! And he's wearing my clothes!"

"But…" Realisation was beginning to dawn on Clara. "You don't mean…"

The mysterious figure stepped forward. "Come on, Clara!" he said. "Wakey wakey! It's me! The one and only!"

Clara looked at him in shock.

The stranger's face broke into a wide grin. "I'm the Doctor!"


	2. Fight the Future

2

Fight the Future

"And now," said the newcomer, "if it's all right with you, I think I'm going to fall over again." He sagged, and fell against the TARDIS console.

Both Clara and the Doctor rushed forward to grab him. They helped him back until he was leaning against the railing. "There we go. Steady now," said the Doctor. "He's just regenerated," he said to Clara. "He'll be a bit unsteady."

"But I don't understand," said Clara. "He's you?"

"Yeah," said the Doctor. "Me from the future. When the TARDIS merged with the future version of itself, he got left behind."

"By accident?"

"No," said the Doctor. "The likelihood of the two TARDISes both having their barriers down and both _just so happening_ to collide with one another in the whole of time and space? No way. This was a deliberate act." He looked at the Other Doctor – his future self. "I just want to know _why_."

"Can't help you there," said the Other Doctor. "I can't remember why."

"Oh, well that's convenient," snapped the Doctor. "You cross back into your own timestream – breaking the most fundamental rule of time travel – and you can't remember why you did it?"

"It is convenient, though, isn't it?" the other one replied.

The Doctor thought about it. "You're right," he said, his expression softening slightly. "It's better this way. But just tell me one thing – is it soon?"

The Other Doctor hesitated for a moment. "Yes," he said at last. "At least, I think so. Certainly, my last memories are of being you."

"Right," the Doctor said quietly.

Clara was again aware of a significant conversation happening that she wasn't part of. She decided to just stay silent for the time being. The Doctor would presumably explain when he got the chance.

The Doctor's temporarily darkened mood had suddenly passed. "Well then!" he said brightly. "Let's not waste any time! Come on, Clara. Let's help him into one of the side rooms, where he can have a lie down."

Clara obeyed. They both took an arm and gently guided the Other Doctor down the steps and out of the main console room.

As they walked, a though occurred to Clara. "Should you be doing that?" she said. "Touching him, I mean."

"Technically, it's a bad idea," said the Doctor. "Coming into contact with your past or future self can trigger a wound in time. Pretty nasty."

"How nasty?"

"Big flying bat things materialise and eat you."

They walked in silence for a moment as Clara digested this. "Soooo," she said, "are you going to let go of him?"

"Well, from my experience, Time Lords can usually get away with interacting with separate regenerations. If he was still me – as in, this face – we'd be in trouble. As it is, though, I can touch myself all I want."

There was a pause. "Yeah," said Clara, "You have fun with that."

After the Other Doctor had been safely installed on a comfortable sofa in one of the side rooms, Clara and the Doctor returned to the main console room.

"So," said Clara. "That's the future you. That's what you're going to turn into."

"I guess so," said the Doctor. He grinned. "I'm going to be ginger. I always wanted to be ginger."

"Can't you control it?"

"Sometimes," said the Doctor. "If it's an intentional regeneration, you can generally get whatever you want. If it's forced on you – which usually happens to me – you can't really control it. You can try to focus on a single thing, but that's about it. I generally just let go completely and see what I get."

"But it'll be something similar to yourself, right?" said Clara.

"More or less. I don't know exactly. But I'm generally happy with what I get... as long as I'm not Scottish. I'd hate to have that accent again." He shuddered.

"Right," said Clara. "So would you care to explain what's going on?"

"I don't fully understand it myself," said the Doctor, "but it think the gist of it is: at some point in the near future, I'm going to regenerate, and the circumstances of said regeneration are bad enough for me to cross back into my own timeline to prevent it happening."

"How do you know that?" said Clara. "He – I mean you – can't remember. Which, as you said, is awfully convenient, isn't it?"

"Actually, it is," said the Doctor. "Post-regenerative amnesia is a fairly common side-effect. His memory will come back in time, don't worry. Or rather, do worry. His amnesia is actually a good thing."

"How?"

"Think about it. Him being here is a paradox. In fact, it's a pair of Docs!" The Doctor grinned. Clara rolled her eyes. "Anyway!" The Doctor continued. "The moment he crossed back to this point in his timestream, he altered the direction of it. That creates a paradox. If he changes the past so he – I – don't regenerate, then he doesn't exist, meaning he couldn't come back in time to change it."

"So, it's a timey wimey thing?" said Clara.

"Yeah. The point is, at the moment, it's only a little paradox. He's only altered the direction of the timestream a little bit. If he had come back and actively prevented me from taking the action that led to him coming back here, then that would have created a whopping great paradox that most certainly would have had terrible consequences for all involved. The less he tells us about the future, and the less he tries to actively interfere in it, the longer we can get away with the paradox. See?"

"Not really," said Clara. "But for the sake of keeping things going, assume that I do."

"It's quite simple," said the Doctor. "Crossing back into your own timestream is an incredibly dangerous and risky thing to do. Whatever is coming in the near future must be something very bad indeed. That's the only reason I can think I would take the risk. So obviously we have to prevent whatever is coming. But as long as we don't know specifically what we're trying to prevent, I think we can get away with the paradox. As soon as we figure it out, or he regains his memory, we're in trouble. Now do you understand?"

Clara shook her head.

The Doctor sighed. "Ok. In really simple terms: we have to figure out what happens in the near future and try to prevent it, without asking him – my future self – directly. We have to use the clues available to us to figure it out instead, in order to prevent the assumedly bad future. It's that simple."

"You could have just said that," said Clara. "It didn't need the complicated and confusing explanation."

"Just because you can't follow it doesn't make it confusing," the Doctor said, somewhat primly.

"Yes, it does!" said Clara. "That's practically the definition of confusing!"

"It doesn't matter!" the Doctor insisted. "Look, just accept that I know what I'm talking about and go with it, alright?"

"That's what I always do," Clara sighed. "All right then, what happens now?"

"Now," said the Doctor, "we try to figure out what is about to happen that is so terrible."

"And how do we do that?"

"Well, let's think. He's pretty sure it's happening soon, from my point of view," said the Doctor. "So, near future. What else? Ah, yes! When we collided, the TARDIS crash landed on Earth!"

"So?"

"We were just drifting aimlessly through space when the collision occurred. The only reason we could have ended up here is that the other TARDIS – the future version – dragged us along with it when it bounced off and returned to its own time."

Clara said, "Can that happen?"

"Why not?" said the Doctor. "It's a sensible explanation."

Clara thought it was very far from a sensible explanation, but had long since decided not to argue with the Doctor when he was invoking his "wibbly-wobbly timey-wimeyness". She shrugged.

"So," the Doctor went on, "we've probably landed somewhere near where the future TARDIS came from. In terms of both time and space." He stopped pacing and began fiddling with the console. "Scanning for recent temporal activity," he said. "Let's see… no sign of my TARDIS at the moment, or in the last few days… which means we're early. Whatever event is due to happen is probably going to be happening in the near future."

"That's convenient," said Clara.

"It is, isn't it? So, where are we? Hmm." The Doctor fiddled a bit more. "East London. We're in a graveyard. Ooh, ominous." He looked up at Clara and grinned.

"It is, though," Clara reminded him. "You might be regenerating in a day or two."

A cloud suddenly passed over the Doctor's face. His grin was gone. "You're right," he said. "So let's see if we can prevent that happening, eh?" He began pacing again. "So," he said, "we have good reason to suspect that something is going to happen in this general area very soon. We ideally want to prevent that something happening, or at least change it in some way. So, where do we start?"

"We could just jump ahead a few days, see what happens, and then jump back here and change it?" Clara suggested.

"Clara, Clara, Clara," said the Doctor, shaking his head. "Once we become a part of events, once we know what's going to happens, we can't change it without causing a massive paradox. That's why it's a good thing my future self has amnesia. If we don't know what's coming, we can still change it."

Clara thought about this. "But what if, by trying to change it, we make the future where you regenerate come true?"

"Ah, the old self-fulfilling prophecy idea. Yes, that is a possibility," said the Doctor. "I honestly have no idea what is going to happen. And isn't that exciting?" The grin was back.

"But-" Clara began.

"Look," said the Doctor. "Time is complicated. As I explained before, it's a big ball of wibbly-wobbly timey-wimey stuff. We could sit here forever and worry about the maybes and the what-ifs, the how-did-that-happens and the is-that-even-possibles. And don't get me started on the but-that-doesn't-make-senses. But if you spend all day analysing these things in great detail, you never actually experience them and miss out on the important things. So just accept my explanation, okay? A future version of me came back in time to send me a warning. I need to figure out what terrible event is about to occur so I can hopefully change it and prevent that future from occurring. That's all there is to it."

Clara looked stunned. "That was quite a speech," she said.

"Sorry," he said. "I just hate it when people overanalyse things. Life is silly sometimes. Just sit back and enjoy the ride without worrying too much about the details, that's my motto."

"It's a good motto," said Clara. "So, what do we do now?"

"I'm not sure," said the Doctor. "Something important is probably going to happen in this area in the next few days, but unless we sit and wait to find out what it is, I'm not really sure what action we can take."

"Check the news?" suggested Clara. "There might be a mention of some big event that could give us a clue."

"Good thinking!" said the Doctor, leaping to the console once more. "Right, I'll run a scan of the biggest local news events. Let's see… ah! What's this?" He pressed a button and the screen changed to a video of a recent news broadcast.

"But we can change that," a woman onscreen was saying. She had an official look about her, with her labcoat and dark hair pulled back into a severe ponytail. "We can change your destiny. We can _Fight the Future_!"

The image cut back to a slightly smarmy newsreader. "That was Doctor Flowers, speaking today at the press conference. Of course, there are many doubters that the device is genuine. But the Foundation is confident that this is the real deal," the newsreader said with a smile. "They have announced the first public demonstration of the device – which they claim can completely rewrite human DNA – will be taking place next Thursday. There's a lot of buzz on social media, using the hashtag #fightthefuture – the slogan of the project. But many sceptics have suggested that such technology is beyond our capabilities at the moment."

"Rewriting DNA?" said Clara. The Doctor shushed her.

"Whether or not these claims hold up will presumably be answered at the demonstration," the newsreader went on. "Of course, although the technology was designed for medical purposes – allowing the elimination of genetic disorders and hereditary diseases – there is no denying that there are cosmetic applications as well. If the device works as promised, people could tweak their bodies as they see fit. Shares in the plastic surgery market are already wobbling. Time will tell whether this device can live up to the hype. Next Thursday, we'll see if they really can fight the future." The newsreader flashed an artificial smile.

The Doctor switched off the screen with a thoughtful look on his face.

"You think that's the one?" Clara asked.

The Doctor nodded. "I've seen this before. A scientist came up with a way to alter the human genetic code. He used it to rejuvenate people and make them younger."

"I remember that," said Clara. "Lazarus, wasn't it? There was some big disaster on the opening night, and afterwards the machine was destroyed and Lazarus was found dead. That was about four of five years ago, I think?"

"For you, maybe. I'm a time traveller. From my point of view, I experienced those events a lot longer ago. I was a different man back then." The Doctor straightened up. "Right!" he said. "I think we should attend this upcoming demonstration. See what all the fuss is about."

"Even though that might lead to your regeneration?"

The Doctor shrugged. "Either I change the future, or I loop round and have another going at it."

A thought had just occurred to Clara. "But if we change the future, he – you – the other Doctor – what will happen to him?"

"If we change the events that led to my regeneration… he'll cease to exist."

There was silence for a moment.

"And he's happy with that arrangement?" said Clara.

"I am," said the Other Doctor, choosing this dramatically appropriate moment to re-enter the room. "Trust me, I know all about the potential consequences. I know this is a paradox. In fact, you could say its a pair of Docs!"

Clara groaned. "Okay," she said. "You're definitely the Doctor."

The Other Doctor smiled for a moment, before his expression turned serious. "While I can't remember exactly why I made the choice to go back on my own timeline, I assume I had a very good reason."

"What reason might that be?" Clara asked.

Both of the Doctors looked at each other. Then back at her.

"What?" she said.

"Why didn't you come with me?" the Doctor said quietly.

"What do you mean?"

"When I travelled back in time to my past self. Why weren't you with me?"

Clara looked back and forth between them. "What are you hinting at?"

"I don't know," said the Doctor. "Maybe nothing at all. Let's not worry about the future until we get there, all right?" He began flicking switches. "So, next Thursday, here we come!"

"We're actually going to do this?" said Clara. "Change your own future?"

The Doctor looked at the Other Doctor, who nodded. "Why not?" said the Doctor. "It's not every day an opportunity like this comes along!"

Clara sighed resignedly. The Other Doctor nodded grimly.

The Doctor straightened his bowtie. "Let's do it!" he said, and, with a flourish, started the TARDIS' engines up. "Let's fight the future!"


End file.
